The invention relates to reinforcement for pneumatic tires for vehicles, consisting of a first belt ply having adjacent its edges lateral strips consisting of a plastic or rubber mixture, and a second belt ply whose marginal portions are folded over to hem in the lateral strips.
A reinforcement ply is disclosed in the Italian Pat. No. 514,343 having a substantially thick first belt ply and lateral strips connected directly to the two outer edges of the first belt ply. The strips continuously decrease in thickness from a starting thickness equal to the thickness of the first belt ply and extend toward the outside of the reinforcement into the area of the folded edge of a second belt ply. The folded over marginal portions of the second belt ply completely enclose the lateral strips, but extend only slightly beyond the outer edges of the first belt ply to barely cover the gap between the outer edges of the first belt ply and its adjacent lateral strips. The large radial thickness of the first belt ply together with the corresponding large radial thickness of the lateral strips results in a relatively large radial thickness of the reinforcement ply. However, this reinforcement construction exhibits adjacent tire width zones of highly differing strength or rigidity wherein the rigidity values experience abrupt changes at the transition points between adjacent zones.